SAFE public projects git trees. - safe/jmp/linux-2.6/blob - security/tomoyo/tomoyo.c

   1 /*
   2  * security/tomoyo/tomoyo.c
   3  *
   4  * LSM hooks for TOMOYO Linux.
   5  *
   6  * Copyright (C) 2005-2009  NTT DATA CORPORATION
   7  *
   8  * Version: 2.2.0   2009/04/01
   9  *
  10  */
  11
  12 #include <linux/security.h>
  13 #include "common.h"
  14 #include "tomoyo.h"
  15 #include "realpath.h"
  16
  17 static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp)
  18 {
  19         new->security = NULL;
  20         return 0;
  21 }
  22
  23 static int tomoyo_cred_prepare(struct cred *new, const struct cred *old,
  24                                gfp_t gfp)
  25 {
  26         /*
  27          * Since "struct tomoyo_domain_info *" is a sharable pointer,
  28          * we don't need to duplicate.
  29          */
  30         new->security = old->security;
  31         return 0;
  32 }
  33
  34 static void tomoyo_cred_transfer(struct cred *new, const struct cred *old)
  35 {
  36         /*
  37          * Since "struct tomoyo_domain_info *" is a sharable pointer,
  38          * we don't need to duplicate.
  39          */
  40         new->security = old->security;
  41 }
  42
  43 static int tomoyo_bprm_set_creds(struct linux_binprm *bprm)
  44 {
  45         int rc;
  46
  47         rc = cap_bprm_set_creds(bprm);
  48         if (rc)
  49                 return rc;
  50
  51         /*
  52          * Do only if this function is called for the first time of an execve
  53          * operation.
  54          */
  55         if (bprm->cred_prepared)
  56                 return 0;
  57         /*
  58          * Load policy if /sbin/tomoyo-init exists and /sbin/init is requested
  59          * for the first time.
  60          */
  61         if (!tomoyo_policy_loaded)
  62                 tomoyo_load_policy(bprm->filename);
  63         /*
  64          * Tell tomoyo_bprm_check_security() is called for the first time of an
  65          * execve operation.
  66          */
  67         bprm->cred->security = NULL;
  68         return 0;
  69 }
  70
  71 static int tomoyo_bprm_check_security(struct linux_binprm *bprm)
  72 {
  73         struct tomoyo_domain_info *domain = bprm->cred->security;
  74
  75         /*
  76          * Execute permission is checked against pathname passed to do_execve()
  77          * using current domain.
  78          */
  79         if (!domain)
  80                 return tomoyo_find_next_domain(bprm);
  81         /*
  82          * Read permission is checked against interpreters using next domain.
  83          * '1' is the result of open_to_namei_flags(O_RDONLY).
  84          */
  85         return tomoyo_check_open_permission(domain, &bprm->file->f_path, 1);
  86 }
  87
  88 #ifdef CONFIG_SYSCTL
  89
  90 static int tomoyo_prepend(char **buffer, int *buflen, const char *str)
  91 {
  92         int namelen = strlen(str);
  93
  94         if (*buflen < namelen)
  95                 return -ENOMEM;
  96         *buflen -= namelen;
  97         *buffer -= namelen;
  98         memcpy(*buffer, str, namelen);
  99         return 0;
 100 }
 101
 102 /**
 103  * tomoyo_sysctl_path - return the realpath of a ctl_table.
 104  * @table: pointer to "struct ctl_table".
 105  *
 106  * Returns realpath(3) of the @table on success.
 107  * Returns NULL on failure.
 108  *
 109  * This function uses tomoyo_alloc(), so the caller must call tomoyo_free()
 110  * if this function didn't return NULL.
 111  */
 112 static char *tomoyo_sysctl_path(struct ctl_table *table)
 113 {
 114         int buflen = TOMOYO_MAX_PATHNAME_LEN;
 115         char *buf = tomoyo_alloc(buflen);
 116         char *end = buf + buflen;
 117         int error = -ENOMEM;
 118
 119         if (!buf)
 120                 return NULL;
 121
 122         *--end = '\0';
 123         buflen--;
 124         while (table) {
 125                 if (tomoyo_prepend(&end, &buflen, table->procname) ||
 126                     tomoyo_prepend(&end, &buflen, "/"))
 127                         goto out;
 128                 table = table->parent;
 129         }
 130         if (tomoyo_prepend(&end, &buflen, "/proc/sys"))
 131                 goto out;
 132         error = tomoyo_encode(buf, end - buf, end);
 133  out:
 134         if (!error)
 135                 return buf;
 136         tomoyo_free(buf);
 137         return NULL;
 138 }
 139
 140 static int tomoyo_sysctl(struct ctl_table *table, int op)
 141 {
 142         int error;
 143         char *name;
 144
 145         op &= MAY_READ | MAY_WRITE;
 146         if (!op)
 147                 return 0;
 148         name = tomoyo_sysctl_path(table);
 149         if (!name)
 150                 return -ENOMEM;
 151         error = tomoyo_check_file_perm(tomoyo_domain(), name, op);
 152         tomoyo_free(name);
 153         return error;
 154 }
 155 #endif
 156
 157 static int tomoyo_path_truncate(struct path *path, loff_t length,
 158                                 unsigned int time_attrs)
 159 {
 160         return tomoyo_check_1path_perm(tomoyo_domain(),
 161                                        TOMOYO_TYPE_TRUNCATE_ACL,
 162                                        path);
 163 }
 164
 165 static int tomoyo_path_unlink(struct path *parent, struct dentry *dentry)
 166 {
 167         struct path path = { parent->mnt, dentry };
 168         return tomoyo_check_1path_perm(tomoyo_domain(),
 169                                        TOMOYO_TYPE_UNLINK_ACL,
 170                                        &path);
 171 }
 172
 173 static int tomoyo_path_mkdir(struct path *parent, struct dentry *dentry,
 174                              int mode)
 175 {
 176         struct path path = { parent->mnt, dentry };
 177         return tomoyo_check_1path_perm(tomoyo_domain(),
 178                                        TOMOYO_TYPE_MKDIR_ACL,
 179                                        &path);
 180 }
 181
 182 static int tomoyo_path_rmdir(struct path *parent, struct dentry *dentry)
 183 {
 184         struct path path = { parent->mnt, dentry };
 185         return tomoyo_check_1path_perm(tomoyo_domain(),
 186                                        TOMOYO_TYPE_RMDIR_ACL,
 187                                        &path);
 188 }
 189
 190 static int tomoyo_path_symlink(struct path *parent, struct dentry *dentry,
 191                                const char *old_name)
 192 {
 193         struct path path = { parent->mnt, dentry };
 194         return tomoyo_check_1path_perm(tomoyo_domain(),
 195                                        TOMOYO_TYPE_SYMLINK_ACL,
 196                                        &path);
 197 }
 198
 199 static int tomoyo_path_mknod(struct path *parent, struct dentry *dentry,
 200                              int mode, unsigned int dev)
 201 {
 202         struct path path = { parent->mnt, dentry };
 203         int type = TOMOYO_TYPE_CREATE_ACL;
 204
 205         switch (mode & S_IFMT) {
 206         case S_IFCHR:
 207                 type = TOMOYO_TYPE_MKCHAR_ACL;
 208                 break;
 209         case S_IFBLK:
 210                 type = TOMOYO_TYPE_MKBLOCK_ACL;
 211                 break;
 212         case S_IFIFO:
 213                 type = TOMOYO_TYPE_MKFIFO_ACL;
 214                 break;
 215         case S_IFSOCK:
 216                 type = TOMOYO_TYPE_MKSOCK_ACL;
 217                 break;
 218         }
 219         return tomoyo_check_1path_perm(tomoyo_domain(),
 220                                        type, &path);
 221 }
 222
 223 static int tomoyo_path_link(struct dentry *old_dentry, struct path *new_dir,
 224                             struct dentry *new_dentry)
 225 {
 226         struct path path1 = { new_dir->mnt, old_dentry };
 227         struct path path2 = { new_dir->mnt, new_dentry };
 228         return tomoyo_check_2path_perm(tomoyo_domain(),
 229                                        TOMOYO_TYPE_LINK_ACL,
 230                                        &path1, &path2);
 231 }
 232
 233 static int tomoyo_path_rename(struct path *old_parent,
 234                               struct dentry *old_dentry,
 235                               struct path *new_parent,
 236                               struct dentry *new_dentry)
 237 {
 238         struct path path1 = { old_parent->mnt, old_dentry };
 239         struct path path2 = { new_parent->mnt, new_dentry };
 240         return tomoyo_check_2path_perm(tomoyo_domain(),
 241                                        TOMOYO_TYPE_RENAME_ACL,
 242                                        &path1, &path2);
 243 }
 244
 245 static int tomoyo_file_fcntl(struct file *file, unsigned int cmd,
 246                              unsigned long arg)
 247 {
 248         if (cmd == F_SETFL && ((arg ^ file->f_flags) & O_APPEND))
 249                 return tomoyo_check_rewrite_permission(tomoyo_domain(), file);
 250         return 0;
 251 }
 252
 253 static int tomoyo_dentry_open(struct file *f, const struct cred *cred)
 254 {
 255         int flags = f->f_flags;
 256
 257         if ((flags + 1) & O_ACCMODE)
 258                 flags++;
 259         flags |= f->f_flags & (O_APPEND | O_TRUNC);
 260         /* Don't check read permission here if called from do_execve(). */
 261         if (current->in_execve)
 262                 return 0;
 263         return tomoyo_check_open_permission(tomoyo_domain(), &f->f_path, flags);
 264 }
 265
 266 /*
 267  * tomoyo_security_ops is a "struct security_operations" which is used for
 268  * registering TOMOYO.
 269  */
 270 static struct security_operations tomoyo_security_ops = {
 271         .name                = "tomoyo",
 272         .cred_alloc_blank    = tomoyo_cred_alloc_blank,
 273         .cred_prepare        = tomoyo_cred_prepare,
 274         .cred_transfer       = tomoyo_cred_transfer,
 275         .bprm_set_creds      = tomoyo_bprm_set_creds,
 276         .bprm_check_security = tomoyo_bprm_check_security,
 277 #ifdef CONFIG_SYSCTL
 278         .sysctl              = tomoyo_sysctl,
 279 #endif
 280         .file_fcntl          = tomoyo_file_fcntl,
 281         .dentry_open         = tomoyo_dentry_open,
 282         .path_truncate       = tomoyo_path_truncate,
 283         .path_unlink         = tomoyo_path_unlink,
 284         .path_mkdir          = tomoyo_path_mkdir,
 285         .path_rmdir          = tomoyo_path_rmdir,
 286         .path_symlink        = tomoyo_path_symlink,
 287         .path_mknod          = tomoyo_path_mknod,
 288         .path_link           = tomoyo_path_link,
 289         .path_rename         = tomoyo_path_rename,
 290 };
 291
 292 static int __init tomoyo_init(void)
 293 {
 294         struct cred *cred = (struct cred *) current_cred();
 295
 296         if (!security_module_enable(&tomoyo_security_ops))
 297                 return 0;
 298         /* register ourselves with the security framework */
 299         if (register_security(&tomoyo_security_ops))
 300                 panic("Failure registering TOMOYO Linux");
 301         printk(KERN_INFO "TOMOYO Linux initialized\n");
 302         cred->security = &tomoyo_kernel_domain;
 303         tomoyo_realpath_init();
 304         return 0;
 305 }
 306
 307 security_initcall(tomoyo_init);